It is known to dye keratin fibers, in particular hair, with dyeing compositions containing oxidation dyes. Oxidation dyes typically comprise oxidation dye precursors and couplers. Oxidation dye precursors, generally called oxidation bases, are colorless or weakly colored compounds which, combined with oxidizing agents, can give rise to colored and dye compounds by a process of oxidative condensation. They are in particular ortho- or para-phenylenediamines, ortho- or para-aminophenols, or heterocyclic bases. The shades obtained with these oxidation bases may be modified by combining the oxidation bases with couplers or color modifiers, the couplers being chosen in particular from aromatic meta-diamines, meta-aminophenols, meta-diphenols and certain heterocyclic compounds. The variety of molecules used in oxidation bases and couplers allows a rich palette of colors to be obtained.
The oxidation dyeing method generally consists in applying to keratin fibers oxidation bases or a mixture of oxidation bases and couplers with an oxidizing agent, most often hydrogen peroxide, in allowing to act, and then in rinsing the keratin fibers.
Due to the reactivity between the oxidation bases with or without couplers and the oxidizing agent, they generally have to be separately formulated into two parts—(1) a coloration part which contains the oxidation bases with or without couplers, and (2) a developer part which contains the oxidizing agent. Both of the two parts are mixed just before coloring the keratin fibers, and applied to the keratin fibers.
In order to facilitate the coloring of keratin fibers, each of oxidation bases, couplers and oxidizing agents is solved or dispersed in a medium, usually in the form of a powder, cream, gel, and the like, in each of the coloration part and the developer part.
The media for coloring keratin fibers make it easy to handle coloring products for keratin fibers. However, additional production processes and costs are necessary to prepare the formulations for the coloration part and the developer part. In addition, it is necessary to carefully select the media to ensure the compatibility with active substances such as oxidation bases, couplers and oxidizing agents.